M. M. Mahfuz Siraz

I. Naturally occurring radioactive materials (NORMs) are integral parts of the Earth’s crust and are mainly associated with the decay chains of 238U and 232Th, as well as primordial radionuclides s...

This study presents a comparative analysis of natural radioactivity and radiological hazard parameters in core samples from the Titas and Rashidpur gas fields, Bangladesh, determined using a high-purity germanium (HPGe) detector. Six core samples from Titas (depths: 2713–2784 m) and four from Rashidpur (depths: 1454–2896 m) were analyzed for the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K. The radionuclide concentrations in Titas range from 17 ± 2 to 64 ± 4 Bq/kg for ²²⁶Ra, 43 ± 3 to 109 ± 4 Bq/kg for ²³²Th, and 787 ± 47 to 2701 ± 70 Bq/kg for ⁴⁰K; while in Rashidpur, the concentrations of ²²⁶Ra range from 32 ± 3 to 52 ± 3 Bq/kg; those of ²³²Th, from 48 ± 3 to 88 ± 4 Bq/kg; and those of ⁴⁰K, from 660 ± 33 to 1737 ± 63 Bq/kg, both surpassing the global average significantly. Assessment of radiological hazard parameters indicates that some values in the Titas samples and a few in the Rashidpur samples exceed internationally recommended reference levels. These findings highlight the importance of continued monitoring and suggest that caution should be exercised when handling or utilizing materials from these gas fields for any purpose.

1. Ionizing radiation is an inherent component of the natural environment, originating primarily from naturally occurring radioactive materials (NORMs) such as 40K, 238U, 232Th, and their decay pro...

Naturally occurring radioactive materials (NORMs) can accumulate in surface dust near industrial zones and, upon inhalation, may pose potential health hazards. This study reports the activity concentrations of NORMs in dust collected from Savar Upazila, one of the most industrialized areas in Bangladesh. A total of 20 dust samples were collected from the vicinity of different industries and analyzed using a high-purity germanium (HPGe) detector. The measured concentrations of ²²⁶ Ra, ²³² Th, and ⁴⁰ K ranged from 17 ± 1 to 32 ± 2, 22 ± 2 to 51 ± 5, and 350 ± 25 to 520 ± 42 Bq/kg, respectively, with mean values below or close to the corresponding world averages of 30, 35, and 400 Bq/kg, respectively. ²²⁶ Ra levels stayed below the global average, but a few samples showed higher ²³² Th and ⁴⁰ K, which is probably due to local geology and some industrial influence. All the radiological hazard parameters were found within the international safety limits. These findings indicate that street dust in Savar does not show significant enrichment of NORMs and poses negligible radiological health risks to pedestrians and nearby residents. Nevertheless, continuous monitoring is recommended to ensure environmental and occupational safety in this rapidly industrializing region.

This pioneering study investigates the levels of naturally occurring radioactive materials in soil collected from the vicinity of Srikail gas field, Bangladesh, utilizing a high purity germanium (HPGe) detector. Forty soil samples were systematically collected from concentric circles around the gas well, with approximate radii of 100, 200, 300, 400, and 500 m. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K ranged from 12-27, 24-45, and 255-480 Bq/kg, respectively, with most values aligning with global averages of 35, 35 and 400 Bq/kg respectively. Notably, two samples showed the presence of artificial radioactivity (¹³⁷Cs). All the radiological hazard indices are well within the recommended safety limits. However, this study emphasizes the need to establish baseline data for the soon-to-be-commissioned Rooppur Nuclear Power Plant and its nearby areas. It also highlights the importance of regular monitoring to detect any future changes in radioactivity levels that might come from natural processes or human activities.

Environmental radioactivity is significantly elevated by coal combustion, posing risks to communities living near coal-fired thermal power plants (CFTPPs). This study presents the first comprehensive assessment of radiological impacts around the Rampal Thermal Power Plant, a 1320 MW facility located in Rampal Upazila, near the UNESCO World Heritage site of Sundarbans, Bangladesh. Thirty soil samples were systematically collected from distances of 100, 500, 1000, 2000, and 3000 m from the power plant. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in soil ranged from 17-31, 29-51, and 350-670 Bq kg^-1, respectively, with a few samples exceeding the population-weighted global averages for ²²⁶Ra (32 Bq kg^-1) and ²³²Th (45 Bq kg^-1), and almost all the samples exceeding the average for ⁴⁰K (420 Bq kg^-1). The elevated levels of ²²⁶Ra, ²³²Th, and ⁴⁰K in the soil samples can be attributed to several interconnected factors, including the presence of thorium-rich minerals such as monazite and zircon, granitic geological formations, and anthropogenic inputs like bottom ash discharge from the plant and coal combustion byproducts. While the radium equivalent activity and hazard indices generally fell within safety limits, the higher outdoor and indoor absorbed dose rates, effective doses, and increased lifetime cancer risk raised alarms about potential health threats for nearby residents over time. Moreover, the long-term radiological effects on the Sundarbans ecosystem could disturb its fragile balance, impacting both biodiversity and the local communities that rely on its resources. These results highlight the necessity for further evaluations and remediation efforts to ensure the safe use of these soils in agricultural and construction activities. This research also seeks to develop a radiological distribution map, which will provide crucial baseline data for the forthcoming Rooppur Nuclear Power Plant.

Assessing soil radioactivity and associated risks in areas surrounding gas fields is essential due to potential natural radionuclide accumulation during extraction activities. This study investigates the radioactivity levels in surface soil from the Haripur gas field. 21 soil samples were analyzed using a high purity germanium (HPGe) detector. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in the soil samples were found to range between 11-19, 20-38, and 280-500 Bq kg^-1, respectively. All ²²⁶Ra values and the majority of ²³²Th and ⁴⁰K values fell within the global average levels for soil, which are 35, 30, and 400 Bq kg^-1, respectively. Radiation hazard indices were found to be below the internationally accepted safety limits set by organizations such as the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) and the International Commission on Radiological Protection (ICRP), indicating that the soil poses no significant radiological risks for construction and agricultural applications. This research offers essential baseline data on soil radioactivity at the Haripur gas field, supporting public health, environmental protection, and regulatory compliance efforts.